After a recent format and installation of XP, I was going to put all of my MP3s back on from the CD-Rs that I used to back them up. I had a total of 4 CD-Rs full of MP3s. The first two were fine, got all of the files off. The second two, on the other hand, had problems. It would copy some files to my designated folder just fine. Some of my files weren't able to be copied though. When it went to copy a file that wouldn't work, it would freeze up and then about a minute later it would say "Cyclic Error: Redundancy Check" and gave a few numbers. Weird thing is, I tried to play those MP3s that wouldn't work from the CD and it (Windows Media Player) played them, all the way through too. What's the dealio? No big deal really, I only lost about 20 files. I'll just download those again. I just don't want this to happen in the future.